This grant is the biological part of a collaborative study of the psychobiology of depression. There is a biological part and a separately numbered and funded clinical part. The biological part is obtaining information on patients with primary affective disorder and, as comparison groups, other psychiatrically ill patients, normal controls, and patients who receive a lumbar puncture as part of their routine workup in neurology, and who consent in writing to a lumbar puncture by the study group. The chemical constituents measured include plasma levels of tricyclic antidepressants, spinal fluid levels of HVA, HIAA and MHPG. There will also be an tolerance test and dexamethasone suppression test to test the hypothalmic pituitary axis. The intention is to have approximately 500 subjects and controls so that there will be a large enough sample from which to make inferences concerning the meaning of the biological results found.